Different cell types make up tissues and organs hierarchically and communicate within a complex, three-dimensional (3D) en- vironment. The in vitro recapitulation of tissue-like structures is meaningful, not only for fundamental cell biology research, but also for tissue engineering (TE). Currently, TE research adopts either the top-down or bottom-up approach. The top-down approach involves defining the macroscopic tissue features using biomaterial scaffolds and seeding cells into these scaffolds. Conversely, the bottom-up approach aims at crafting small tissue building blocks with precision-engineered structural and functional microscale features, using physical and/or chemical approaches. The bottom-up strategy takes advantage of the repeating structural and functional units that facilitate cell-cell interactions and cultures multiple cells together as a functional unit of tissue. In this review, we focus on currently available microscale methods that can control mammalian cells to assemble into 3D tissue-like structures.
Hydrogen sulfide(H_2S)has been found to be the third most important endogenous gaseous signaling molecule after nitric oxide(NO)and carbonic oxide(CO)and plays crucial roles in living organisms and biological systems.Here we use aggregation-induced emission(AIE)of a small organic molecule(TPE-indo)to detect H_2S in both solution and living cells.TPE-indo can target mitochondria and aggregate to fluoresce,which can serve as a sensor for monitoring H_2S in the mitochondria.We regulate the fluorescence of AIE molecules by tuning the viscosity of the solution to form TPE-indo nanoparticles,constructing a probe for H_2S with good selectivity and high sensitivity.The nucleophilic addition of HS-to the TPE-indo is crucial for the rapid H_2S detection.The imaging and analysis of H_2S in mitochondria of living cells with the probe demonstrate potential biological applications.
Yi ZhangXianhong HuangWenwen LiuGuanxin ZhangDeqing ZhangXingyu Jiang
